The present invention relates to an apparatus for decoding a text having information which is compressed by a redundancy suppression encoding system as used in a facsimile and for displaying the decoded information, and more particularly to an information processing system having decode, write and read means suitable for an electronic filing apparatus.
Major methods for representing the content of a document include raster graphics content architecture, character content architecture and geometric graphics content architecture as shown in FIG. 10. The first architecture employs an MH (modified Huffman) code, an MR (modified READ) code or an MMR (modified modified READ) code. The second architecture uses a character code. The third method uses a vector code.
When text information is to be displayed on a display device, it is necessary to periodically read a display memory which the text information is stored, for purposes for refreshing the display in view of the nature of the display device. An apparatus which can write information into the display memory without interrupting the display in the geometric graphics content architecture is disclosed in Microcomputer Application International Conference '84, pages 279 to 286.
However, in the raster graphics content architecture, no consideration has been made to decode compressed text information to an original pixel signal and write the pixel signal into the display memory without interrupting the display.
There is no decode function in the prior art raster graphics content architecture and it must be attained by separate means. An apparatus having a decode function is disclosed in the Technical Journal of The Institute of Electronics and Communication Engineers of Japan, IE84-17 and JP-A-No. 59-126368. In those prior art apparatuses, no consideration is given to writing a decoded pixel signal into a display memory without interrupting the display and displaying the pixel signal under decoding serially on the display device, and it is not possible to review the content of the text until one page or one screen of information has been decoded.